首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   2251篇
  免费   159篇
  国内免费   70篇
耳鼻咽喉   36篇
儿科学   51篇
妇产科学   88篇
基础医学   127篇
口腔科学   5篇
临床医学   119篇
内科学   677篇
皮肤病学   3篇
神经病学   223篇
特种医学   23篇
外科学   767篇
综合类   189篇
预防医学   12篇
眼科学   19篇
药学   82篇
  2篇
中国医学   27篇
肿瘤学   30篇
  2024年   4篇
  2023年   23篇
  2022年   45篇
  2021年   55篇
  2020年   83篇
  2019年   78篇
  2018年   68篇
  2017年   68篇
  2016年   53篇
  2015年   61篇
  2014年   114篇
  2013年   151篇
  2012年   88篇
  2011年   106篇
  2010年   93篇
  2009年   108篇
  2008年   147篇
  2007年   135篇
  2006年   91篇
  2005年   114篇
  2004年   76篇
  2003年   71篇
  2002年   77篇
  2001年   74篇
  2000年   54篇
  1999年   39篇
  1998年   62篇
  1997年   46篇
  1996年   23篇
  1995年   25篇
  1994年   28篇
  1993年   23篇
  1992年   30篇
  1991年   31篇
  1990年   27篇
  1989年   28篇
  1988年   11篇
  1987年   9篇
  1986年   6篇
  1985年   7篇
  1984年   12篇
  1983年   10篇
  1982年   7篇
  1981年   2篇
  1980年   5篇
  1979年   2篇
  1978年   3篇
  1977年   3篇
  1975年   1篇
  1973年   2篇
排序方式: 共有2480条查询结果,搜索用时 15 毫秒
41.
目的:分析临床超低位直肠癌保肛手术(SSO)中实施腹腔镜下经肛门括约肌间切除术(ISR)的临床效果。方法:选取本院收治的超低位SSO患者80例作为研究对象,随机分为两组,每组40例。对照组实施开腹处理,而研究组实施腹腔镜下ISR处理,观察记录两组患者手术时间、术中出血量、住院时间、并发症发生率,并对比分析。结果:研究组手术时间、术中出血量、住院时间、并发症发生率均明显优于对照组,前后比较差异具有统计学意义(P<0.05)。结论:超低位直肠癌保肛手术患者实施腹腔镜下ISR治疗可取得良好的效果,所需手术时间短、出血少、住院时间短以及并发症发生率低,值得临床推广应用。  相似文献   
42.
The internal anal sphincter, the smooth muscle component of the anal sphincter complex, has an ambiguous role in maintaining anal continence. Despite its significant contribution to resting anal canal pressures, even total division of the internal anal sphincter in surgery for anal fistulas may fail to compromise continence in otherwise healthy subjects. However, recently reported abnormalities of the innervation and reflex response of the internal anal sphincter in patients with fecal incontinence indicate its significance in maintaining continence. The advent of sphincter-saving surgery and restorative proctocolectomy has re-emphasized the major contribution of the internal anal sphincter to resting pressure and its significance in preventing fecal leakage. The variable effect of rectal excision on rectoanal inhibitory reflex has led to a reappraisal of the significance of this reflex in discrimination of rectal contents and its impact on anal continence. Electromyographic, manometric, and ultrasonographic evaluation of the internal anal sphincter has provided new insights into its pathophysiology. This article reviews advances in our understanding of internal anal sphincter physiology in health and disease.  相似文献   
43.
Theoretically, relative distal common bile duct obstruction due to sphincter of Oddi dysfunction may be a cause of poor gallbladder evacuation observed on quantitative cholescintigraphy. In this study, the relationship of sphincter of Oddi dysfunction to the gallbladder ejection fraction by quantitative cholescintigraphy was explored. Eighty-one patients with biliary-type pain and otherwise normal evaluations underwent quantitative cholescintigraphy, sphincter of Oddi manometry, and ERCP. Abnormalities of stimulated quantitative cholescintigraphy and/or sphincter of Oddi manometry were present in 70% of this study group. Manometric evidence of sphincter dysfunction was present in patients with similar frequency irrespective of the degree of gallbladder evacuation. In conclusion, abnormalities of quantitative cholescintigraphy and sphincter manometry appear to be independent factors, although frequent findings in this patient population.  相似文献   
44.
PURPOSE: Sacral spinal nerve stimulation is a new therapeutic approach for patients with severe fecal incontinence owing to functional deficits of the external anal sphincter. It aims to use the morphologically intact anatomy to recruit residual function. This study evaluates the long-term results of the first patients treated with this novel approach applying two techniques of sacral spinal nerve stimulator implantation. METHODS: Six patients underwent either of two techniques for electrode placement: one closed (electrodes placed through the sacral foramen) and one open (cuff electrodes placed after sacral laminectomy). Follow-up evaluation of their continence status ranged from 5 to 66 months. RESULTS: Incontinence improved in all patients. The percentage of incontinent bowel movements decreased during chronic stimulation from a mean of 40.2 percent to 2.8 percent, and the Wexner score decreased from a mean of 17 to 2. The function of the striated anal sphincter improved during chronic stimulation: maximum squeeze pressure increased from a mean of 48.5 mmHg to 92.7 mmHg, and median squeeze pressure increased from a mean of 37.3 mmHg to 72.5 mmHg. No complications were encountered perioperatively or postoperatively. Two devices had to be removed because of intractable pain, in one patient at the site of the electrode after five months and in the other at the site of the impulse generator after 45 months. CONCLUSION: Long-term sacral spinal nerve stimulation persistently improves continence and increases striated anal sphincter function in patients with fecal incontinence owing to functional deficits, but in whom the striated anal sphincter is morphologically intact. Two different operative approaches can be applied effectively.Supported by grants from Bayerischen Chirurgen e.V., Munich, Germany; Wilhelm Sander Stiftung, Neustadt, Germany; and Bakken Research Center, Medtronic, Maastricht, the Netherlands.A preliminary report of this study was presented as a poster at the meeting of The American Society of Colon and Rectal Surgeons, San Antonio, Texas, May 2 to 7, 1998.  相似文献   
45.
Objectives: To determine the risk of recurrent anal sphincter rupture (ASR), and compare the risk of anal incontinence (AI) after recurrent ASR, with that seen in women with previous ASR who deliver by caesarean section or vaginally without sustaining a recurrent ASR.

Methods: Women with recurrent ASR between January 2000 and June 2011 were identified at two delivery wards in Copenhagen. The women answered a questionnaire with a validated scoring system for AI (St. Mark`s score), and the results were compared with those obtained in two control groups: women with subsequent uncomplicated vaginal delivery or caesarean section.

Results: There were 93?437 vaginal deliveries. ASR occurred in 5.5% (n?=?2851) of the nulliparous and 1.5% (n?=?608) of the multiparous women. Recurrent ASR occurred in 8% (n?=?49) of whom 50% reported symptoms of AI. We found no difference in the occurrence of AI between women with recurrent ASR, and those who delivered vaginally without repeat ASR (p?=?0.37; OR?=?2.0) or by caesarean section (p?=?0.77; OR?=?1.3).

Conclusion: Women with a past history of ASR have an 8% risk of recurrence. AI affects half of the women with recurrent ASR. Larger studies are required to confirm our findings.  相似文献   

46.
Introduction: Although measuring the pressure of the sphincter of Oddi and the bile duct is considered to be an important examination, called Sphincter of Oddi manometry (SOM), some complications related to the SOM device remain unsolved.

Material and methods: To decrease adverse complications, we developed a 0.46?mm manometry and we performed some in vitro studies.

Results: We successfully developed a 0.46?mm SOM. The diameter is the thinnest size used in endoscopic examinations. The results of in vitro studies show the suitability as SOM.

Conclusion: This device will decrease the risks related to SOM examination. To confirm the safety and feasibility, further studies including in vivo studies will be needed.  相似文献   
47.
Objectives: The cause–effect relationship between bronchial asthma and gastro-esophageal reflux (GER) is known, but studies have not been able to confirm the improvement of lung function with anti-acid therapy. Hypotensive lower esophageal sphincter (LES) may lead to both acid and non-acid reflux, resulting in asthma symptoms and decreased lung function. The objectives of our study were, firstly, to compare basal LES pressure between adult patients of asthma and normal controls and, secondly, to correlate the basal LES pressure with spirometric parameters in these patients. Methods: Thirty patients, aged between 18 and 65 years, diagnosed as cases of bronchial asthma and 27 healthy controls were included in the study. All the participants were subjected to esophageal manometry after overnight fasting and basal LES pressures were recorded. Then, spirometry was done 2?h after meal and pre- and post-bronchodilator FEV1, FVC, PEFR were obtained for the asthma group. Results and conclusions: There is significant difference between basal LES pressure in patients of bronchial asthma and control population (8.70?±?2.67?mmHg versus 16.64?±?5.52, p?<?0.0001). 66.67% of the asthma patients have reduced LES pressures (<10?mmHg). The correlation coefficient between basal LES pressure and prebronchodilator FEV1% predicted is 0.596 (p?<?0.0001, 95% CI 0.3002–0.7872). Obstructive airway impairment in adult patients of bronchial asthma is associated with hypotensive LES. GER, due to hypotensive LES may contribute to deterioration of spirometric parameters in asthma patients.  相似文献   
48.
Objective This study aims to evaluate the diagnostic precision of endoanal magnetic resonance imaging in identifying anal sphincter injury and/or atrophy when compared with either endoanal ultrasound or surgical diagnosis. Materials and methods Quantitative meta-analysis was performed on nine studies, comparing endoanal MRI with endoanal ultrasound or surgical diagnosis in 157 patients. Sensitivity, specificity, and diagnostic odds ratio were calculated for each study. Summary receiver operating characteristic curves (SROC) and subgroup analysis were undertaken. Results The overall sensitivity and specificity of endoanal MRI for external sphincter injury was 0.78 (95%CI: 0.66–0.84) and 0.66 (95%CI: 0.51–0.79), respectively. For internal sphincter injury detection, this was 0.63 (95%CI: 0.50–0.74) and 0.71 (95%CI: 0.60–0.81), respectively. For detection of atrophy, this was 0.86 (95%CI: 0.71–0.95) and 0.82 (95%CI: 0.65–0.93), respectively. The area under the SROC curve and diagnostic odds ratio were 0.84 (SE = 0.07) and 6.14 (95%CI: 2.17–17.4) for external sphincter injury, 0.79 (SE = 0.07) and 4.60 (95%CI: 1.75–12.15) for internal sphincter injury, and 0.92 (SE = 0.08) and 21.49 (95%CI: 2.87–160.64) for sphincter atrophy. Conclusion Endoanal MRI was sensitive and specific for the detection of external sphincter injury and especially sphincter atrophy. It may be useful as an alternative to endoanal ultrasound in patients presenting with fecal incontinence, although further clinical studies are needed to identify its best application in clinical practice.  相似文献   
49.
To facilitate pancreatic stone retrieval, four patients with chronic pancreatitis and pancreatic stones underwent endoscopic pancreatic sphincter balloon dilation (EPSBD) rather than pancreatic sphincterotomy. Extracorporeal shock wave lithotripsy combined with endoscopic removal was carried out in three patients. Stone removal following EPSBD was completely successful in all four patients. Patients showed no severe complications during the dilation procedure. In one patient, to prevent pancreatitis, an endoscopic nasopancreatic drain was placed for 1 week after EPSBD. Compared with pancreatic sphincterotomy, EPSBD can be performed safely in patients with chronic pancreatitis to assist in the extraction of pancreatic duct stones. Use of the EPSBD procedure in cases of chronic pancreatitis provides a useful approach to improve endoscopic clearance of pancreatic duct stones.  相似文献   
50.
PURPOSE: Prediction of success after anterior sphincter repair for incontinence is difficult. Standard multivariate analysis techniques have only 75 to 80 percent accuracy. Artificial intelligence, including artificial neural networks, has been used in the analysis of complex clinical data and has proved to be successful in predicting the outcome of other surgical procedures. Using a neural network algorithm, we have assessed the probability of success after anterior sphincter repair. METHODS: Prospective anorectal physiology data of 72 patients undergoing anterior sphincter repair was collected between 1995 and 1999. Complete data sets of 75 percent of the series were used to train an artificial neural network; the remaining 25 percent were used for data validation. The output was continence grading, ranging from 0 to 4 (worse to continent). RESULTS: The outcome at 3, 6, and 12 months postoperatively was obtained and assessed. The best correlation between actual data value and artificial neural network value was found at 12 months (r = 0.931; P = 0.0001). Clear correlations also were found at three months (r = 0.898; P = 0.0001) and six months (r = 0.742; P = 0.002). Results of applying a net to details excluding pudendal nerve latency were poor. CONCLUSIONS: Artificial neural networks are more accurate (93 percent correlation) than standard statistics (75 percent) when applied to the prediction of outcome after anterior sphincter repair. This assessment also confirms the usefulness of pudendal latency in the prediction of anterior sphincter repair outcome. The results obtained highlight the obvious usefulness of artificial neural networks, which could now be used in a prospective evaluation for application of the technique.  相似文献   
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号